I started using the pinned tabs feature in chrome, but I thought it would be awesome if I could get the unread count from a page's title from sites like Twitter (eg (2) Twitter / Home) and overlay that onto the favicon.
The result is a little buggy, but it works. I used HTML canvas to pull the current favicon and overlay the count onto it, then inject it back into the page.
Unread Count on the Chrome Web Store: https://chrome.google.com/webstore/detail/gaohofpopjedmgfigclabbgbnlgmajoa